This invention relates generally to heat pump systems, and more particularly, to a cycle reversing valve for use in heat pump systems.
It is well known to use cycle reversing valves to control the operation of heat pumps. These valves, often referred to as xe2x80x9cfour way valvesxe2x80x9d or xe2x80x9cswitch over valvesxe2x80x9d, are used to reverse the refrigerant line connections to a compressor, such that the heat pump can either pump heat into or out of the area to be heated or cooled.
Cycle reversing valves for use in heat pumps typically are provided with a flow plate through which there are port passages. Flow is controlled by a xe2x80x9cbathtubxe2x80x9d which moves to cover and uncover ports in the flow plate. The bathtub shape requires an abrupt 180 degree turn of the suction flow. However, the xe2x80x9cbathtubxe2x80x9d causes a loss of efficiency or SEER loss. This loss occurs through the suction gas line and the discharge gas line of the heat pump and from heat transfer. In particular, suction gas loss results from the restriction in the flow plate and the 180xc2x0 bend of the bathtub. The discharge gas loss results from abrupt changes in expansion and contraction, as well as from the flow path of the discharge line. Cold suction gas inside the xe2x80x9cbathtubxe2x80x9d, which is surrounded by hot discharge gas, causes heat transfer loss.
Numerous patents are directed to reversing valves which attempt to improve the efficiency of the heat pump and/or simplify its operation by modifying the structure and configuration of the valve member. These valves include ones providing control for the opening or shutting the discharge and suction ports through direction of pressure differential between the high and low side of the system. Other valves use complex switching and control elements, which may include numerous springs, cylinders and pistons, in an attempt to improve the efficiency of the heat pump. Still other valve designs attempted to modify the valve member itself, for example, by providing a butterfly valve, to increase efficiency and simplify construction. Still other valve structures included multiple chambers or multiple valves in an attempt to simplify the design or increase efficiency of the reversing valve.
Overall, most known reversing valves do not sufficiently reduce or limit the losses that occur in heat pumps. Therefore, what was needed was a new reversing valve to reduce or limit efficiency loss, while providing a less complex design for controlling and/or shifting the reversing valve, which had fewer component parts.
The cycle reversing valve of the present invention provides a simple valve design, having few component parts, which provides a direct path through the valve for the suction gas, thereby increasing the efficiency of the system in which the valve is used. The cycle reversing valve of the present invention also provides improved segregation of the gasses within the valve, thereby lowering heat transfer losses.
Generally, the cycle reversing valve provides gas flow paths that provide more efficient and smooth communication of gas than the standard contraction/restriction and 180 degree bend of many known reversing valves. Additionally, in one embodiment magnetic coupling provides for control of the valve member, thereby eliminating braze leak paths and problems with external capillary tubes.
According to one aspect of the present invention, a four port reversing valve for a reversible-cycle refrigeration system having a compressor is constructed with the reversing valve having a first inlet port adapted to be connected to the compressor and second, third, and fourth ports, and further, having a rotatable valve member operable between first and second positions. The valve member in its first position connects the first inlet port with the second port and the third port with the fourth port, and the valve member in its second position connects the first inlet port with the fourth port, and the second port with the third port. The second and third, ports and the third and fourth ports are arranged so that the angle between the ports is greater than about 90xc2x0, more preferably greater than about 120xc2x0, and still more preferably equal to or greater than about 135xc2x0. In one embodiment the valve member is rotated between positions and in another it is translated linearly.
The valve member preferably has a smoothly contoured passage therethrough that connects the third port with the fourth port when the valve member is in its first position and that connects the third port with the second port when the valve member is in its second position, to provide a smooth flow path therethrough.
The four port reversing valve, in one embodiment, further comprises a rotating drive mechanism for rotating the valve member. The valve member is preferably magnetically coupled to the rotating drive mechanism, so that the valve member can be sealed inside the valve. The rotating valve mechanism may be an electric motor, a rotating solenoid, or other suitable drive. Alternatively, the rotating drive mechanism can be connected directly to the valve member. The rotating drive mechanism may be a linked rotary solenoid or hermetic motor.
While the principal advantages and features of the present invention have been explained above, these and other features and advantages will be in part apparent and in part pointed out in a more detailed description of the various embodiments and aspects of the invention as set out below.